Aluminum alloy



Patented June 27, 1933 UNITED STATES PATENT, OFFICE C0 I TBT C. TITUS,OF NEW YORK, N. Y.

ALUMINUM ALLOY No Drawing.

My invention relates to a series of aluminum alloys of novel compositionand properties. The alloys of my invention are particularlycharacterized by the presence of boron, magnesium and silicon. Y

Alloys consisting principally of aluminum and containing substantialamounts of boron, magnesium and silicon are characterized by beinglighter, harder and stronger than aluminum. The amount of magnesium inthe new alloys may vary from about 0.25 to about 5.0%, although it isgenerally desirable to add hot more than about 1.5% of magnesium. Theamount of boron may vary from about 0.05% to about 2.0, although atleast 0.25% is preferable, and in many cases it ispreferable to add notmore than 1% of boron due to the increased brittleness caused by higheramounts. The silicon may advantageously be present in amounts of fromabout 0.5% to about 7.5%, and in general it is preferable that not morethan about 4.5% of silicon be present. The amount of aluminum should ingeneral be at least about 90%. For many purposes it is advantageous touse aluminum in amounts of from about 93% to about 96%.

While the alloys consisting substantially solely of aluminum, magnesium,boron and silicon are valuable for many uses, the alloys areparticularly valuable when they also contain other metals. Alloys ofaluminum, magnesium, boron and silicon containing such metals as copper,nickel, cobalt, zinc, vanadium, tungsten, molybdenum and chromiumprovide a series of alloys characterized by 5 their light weight,together with high hardvness, tensile strength, and resistance tocorrosion. In general, the new alloys have a surprisingly highelectrical conductivity.

The following specific formulae are illusfrom 0.25 to 7.5%,

trative of the wide range of compositions of the invention:

An alloy which is particularly valuable for the manufacture ofelectrical conductors, because of its high conductivity and tensilestrength, has the. following composition:

' Percent Magnesium 0.50 Boron 0.25

a Silicon 0.65 Aluminum Remainder An alloy of high malleability and goodApplication filed April 29,

1933. Serial N0. 688,666.

conductivity is represented by the following composition PercentMagnesium 0.75 Boron 0.50 SiliOOll 3.50 0 Copper 3.00

lummum Remamder The following alloy is characterized by its high tensilestrength: V

Percent Magnesium 1.00

oron 0.50 Silicon" 3.50 Nickel 3.00 7 Aluminum Remainder Another alloyof high tensile strength has the composition:

Percent Magnesium 1.50 Boron 0.75 Silicon 3.00 Cobalt 2.25 AluminumRemainder The presence of vanadium in alloys of the an inventionincreases their tensile strength and toughness and decreases thetendency to crystalhzation in use. An example of a useful alloy of theinvention containing vanadium is the following:

f Percent Magnesium 0.50 Boron 0.35 Silicon 2.75 Nickel 2.65 Vanadium0.75 Aluminum Remainder Metals other than aluminum, magnesium, boron andsilicon may, in general, be present In the alloys. of the invention inamounts of although the presence of not more than 5% of such othermetals is frequently desirable.

In'general it may be said that a principal function of boron in thealloys of the inven tion is to increase the hardness and conductivity ofthe alloys and to increase their resistance to corrosion, a principalfunction of the magnesium is to decrease the specific gravity andincrease the resistance to corrosion, While a principal function of thesilicon 15 to increase the tensile strength and corrosiomresistance andto decrease the specific gravity.

2.7 4, a tensile strength when cast tageously As indicated above, othermetals may be added for the purpose of increasing tensile strength,malleability, resistance to corrosion, electrical conductivity and otherspecial properties.

Alloys of the invention as described above have been obtained having aspecific gravity of from 2.60 to 2.80, more generally 2.66 to of 27,000to 35,000 pounds per square inch, and when mechanically worked of from36,000 to 55,000

ounds; and an electrical conductivity as high as 56 (Ag=100). Rolledsheets of alloys of the invention have shown an elongation at break ashigh as 26%.

The metals may be utilized in the cast condition or they may be rolled,drawn or otherwise worked. Mechanical working is advancarried out at atemperature of 150-450 C. and such working efiects a material increasein the tensile strength of the alloys.

An advantageous method of producing the alloys of the invention is asfollows: The aluminum is melted in a crucible and covered with a layerof powdered charcoal. The. charcoal serves to protect the metal fromoxidation and to reduce those metals which are added the form of oxides.The magnesium and silicon are added as metal and the boron as oxides.Other metals may be added as such or in the form of their oxides,according to the nature of the particular metal. The added metals ortheir oxides are advantageously added enclosed in aluminum capsules. Theboron oxide is preferably added to the melted aluminum first. The othermetals or oxides may be added together.

I claim: Y

1. Alloys consisting principally of aluminum and characterized bycontaining from 0.05% to 2.0% of boron, from 0.25% to 5.0% of magnesium,and from 0.5% to 7.5% of silicon.

2. Alloys consisting principally of aluminum and characterized bycontaining from 0.25% to 1.0% of boron, from 0.25% to 1.5% of magnesium,and from 0.5% to 4.5% of silicon.

3. Alloys consisting principally of aluminum and characterized bycontaining about 0.25% .of boron, about 0.50% of magnesium, and about0.65% of silicon.

Intestimony whereof, I afiix my signature.

' COURT' G. TITUSW

